Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 134-146).

Thesis (MSc (Genetics. Plant Biotechnology))--University of Stellenbosch, 2005. / Sucrose accumulation, marked by a continuous cycle of synthesis and degradation, is characterised by a shift of carbon away from the insoluble matter and respiratory intermediates into sucrose. Despite this shift, a significant proportion of carbon is returned to these pools by hexose-phosphate: triose-phosphate cycling and/or sucrose cycling. Little is known about the magnitude and behaviour of these cycles in sugarcane. Contradictory reports on the relationship between these two cycles have led to the evaluation of the link between the hexose-phosphate: triose-phosphate- and sucrose cycle. In addition, it still needs to be tested whether these cycles could significantly influence carbon partitioning within sugarcane internodal tissue. In this work, a comprehensive metabolic profile was constructed for sugarcane internodal tissue by gas chromatography-mass spectrometry (GC-MS) in order to determine the steady state levels of a broad range of primary metabolites that are involved in these cycles. The power of GC-MS was illustrated by the detection of raffinose, maltose, ribose, xylitol, inositol, galactose, arabinose and quinic acid, which was quantified for the first time in sugarcane internodal tissue. Analyses were not solely based on the prevailing metabolite levels, but also on the interactions between these metabolites. Thus, in a complementary approach the metabolic flux between the two substrate cycles was assessed by 13C nuclear magnetic resonance (NMR). Analyses of transgenic sugarcane clones with 45-95% reduced cytosolic pyrophosphate: D-fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) activity displayed no visual phenotypic change, but significant changes were evident in in vivo metabolite levels. Sucrose concentrations increased six and three-fold in young and maturing internodal tissue, respectively. Reduced PFP activity also resulted in an eight-fold increase in the hexose-phosphate: triose-phosphate ratio in the transgenic immature internodes. In addition, the hexose-phosphate: triose-phosphate cycling decreased in the immature internodes of the transgenic lines if compared to the immature control internode. However, there was no significant difference between the hexose-phosphate: triose-phosphate cycling in the mature internodal tissue of the transgenic and the control lines. This illustrated that PFP mediates hexose-phosphate: triose-phosphate cycling in immature sugarcane internodal tissue. Unpredictably, reduced PFP activity led to a ten-fold increase in sucrose cycling in the transgenic immature internodes. The combination of metabolite profiling and flux distribution measurements demonstrated that the fluxes through the sucrose and the hexose-phosphate pools were not co-regulated in sugarcane internodal tissue. From these observations a model was constructed that implicates higher sucrose cycling as a consequence of increased sucrose concentrations.

No Estado do Paraná, o setor industrial de papel e celulose possui aproximadamente 200 mil hectares de área reflorestada com Pinus . A crescente demanda vem impulsionando a implantação de novas áreas, sendo imprescindível a otimização do uso da área que se apresenta como o fato central da sustentabilidade. Neste contexto, não somente o que diz respeito à produtividade propriamente dita, mas aspectos relativos à qualidade ambiental, como os recursos hídricos e a conservação do solo são importantes para a conservação do ecossistema. Esse trabalho teve como objetivo principal caracterizar a dinâmica hidrológica e a biogeoquímica de duas microbacias, cobertas respectivamente, por Mata Atlântica e Pinus taedaL. As microbacias localizadas na região centro-leste do Estado do Paraná, no Município de Telêmaco Borba, foram selecionadas com a finalidade de realizar medições de precipitação e vazão, durante o período de agosto de 2005 a julho de 2006, e principalmente quantificar o balanço dos nutrientes. De acordo com os resultados, concluiu-se que as duas microbacias apresentaram características semelhantes para a dinâmica hidrológica, para as propriedades do solo e, principalmente para o balanço geoquímico dos nutrientes. Portanto, essas constatações apóiam a hipótese para futuras comparações entre as duas microbacias e permitem inferir que prováveis mudanças que possam ocorrer poderão ser atribuídas às práticas do manejo florestal. / In the State of Paraná, Brasil, the pulp and paper industry holds about 200 thousand hectares of Pine plantatios. An increasing demand has been stimulating the implantation of new areas and this fact requires the optimization of land use practices, that which is itself a central fact for sustainability. In this context, not only from the perspective of the productivity, itself, but also in regards to environmental aspects, such as water resources and the conservation of the soil, which are important for the conservation of the ecosystem. The main objective, of this work was to characterize the hydrological and biogeochemical dynamics of two small catchments, covered wither Rainforest and Pinus taeda L. plantation. The catchments, located in the center east region of the Paraná State, in the municipality of Telêmaco Borba, were selected with the purpose of water balance calculation through continuous measurement of precipitation and streamflow, during the period of August of 2005 until July of 2006, and, mainly, the estimation of the catchment nutrients budget. The results showed that the two catchments presented similar characteristics in hydrological dynamics, as well an in soil properties and, mainly, in the geochemical nutrients budgets. Therefore, these evidences support the hypothesis for future comparisons between the two catchments and allow inferring that probable changes that can occur might be attributed to the practical forest management in one of them.

abstract: Phosphorus (P), an essential element for life, is becoming increasingly scarce, and its global management presents a serious challenge. As urban environments dominate the landscape, we need to elucidate how P cycles in urban ecosystems to better understand how cities contribute to — and provide opportunities to solve — problems of P management. The goal of my research was to increase our understanding of urban P cycling in the context of urban resource management through analysis of existing ecological and socio-economic data supplemented with expert interviews in order to facilitate a transition to sustainable P management. Study objectives were to: I) Quantify and map P stocks and flows in the Phoenix metropolitan area and analyze the drivers of spatial distribution and dynamics of P flows; II) examine changes in P-flow dynamics at the urban agricultural interface (UAI), and the drivers of those changes, between 1978 and 2008; III) compare the UAI's average annual P budget to the global agricultural P budget; and IV) explore opportunities for more sustainable P management in Phoenix. Results showed that Phoenix is a sink for P, and that agriculture played a primary role in the dynamics of P cycling. Internal P dynamics at the UAI shifted over the 30-year study period, with alfalfa replacing cotton as the main locus of agricultural P cycling. Results also suggest that the extent of P recycling in Phoenix is proportionally larger than comparable estimates available at the global scale due to the biophysical characteristics of the region and the proximity of various land uses. Uncertainty remains about the effectiveness of current recycling strategies and about best management strategies for the future because we do not have sufficient data to use as basis for evaluation and decision-making. By working in collaboration with practitioners, researchers can overcome some of these data limitations to develop a deeper understanding of the complexities of P dynamics and the range of options available to sustainably manage P. There is also a need to better connect P management with that of other resources, notably water and other nutrients, in order to sustainably manage cities. / Dissertation/Thesis / M.S. Sustainability 2011

The attribution of recent global warming to anthropogenic emissions is now well established. However, the relation of recent changes in other properties of the climate system to human activities is not as clearly understood. The aim of this thesis is to improve our understanding of this relation in the case of two of these properties, namely the diurnal temperature range (DTR) and modes of tropospheric variability. The DTR, the difference between daily maximum and minimum temperatures, has decreased over global land areas at a rate comparable to the mean warming. Model simulations including the effects of human emissions produce a comparable change, albeit of smaller magnitude. This decrease results from increased reflection of solar radiation by clouds moderated by decreasing soil moisture, mostly through its effect on the ground heat capacity. Recent trends in indices of some modes of atmospheric variability suggest the possibility that forced climate change may manifest itself through a projection onto these pre-existing modes. Model simulations indicate that this is plausible in the case of sea level pressure, but only partly so in the case of surface air temperature. On the interannual time scale examined in this thesis, these projections are consistent with a linear interpretation, rather than a nonlinear one. These results are, however, sensitive to the representation of small scale processes in the models. For instance, the DTR response depends strongly on the representation of cloud and land surface processes. Further examination of the response of one of the tropospheric modes, namely the Southern Annular Mode which represents the meridional shift of the mid latitude jet in the Southern Hemisphere, indicates that it is sensitive to the parametrisation of sub-grid scale mixing in the ocean. Nevertheless, these results suggest that the recent changes are consistent with enhanced greenhouse warming, and indicate that they are likely to continue into the foreseeable future. / Graduate

Forests of the northeastern U.S. help maintain water and air quality by reducing losses of nitrogen (N) into nearby waterways and removing carbon dioxide (CO2) from the atmosphere. However, carbon (C) and N retention in northeastern forests may decrease in response to projected changes in climate, including reductions in winter snowpack and increased soil freezing. Together, these climatic changes may damage tree roots and alter soil processes. Few studies have investigated the extent to which snowpack and soil frost drive C and N fluxes during spring snowmelt, a biogeochemically important period. Similarly, little is known about how changes in winter climate affect above- and belowground CO2 fluxes to the atmosphere. My dissertation combines laboratory and field experiments to quantify the effects of reduced snowpack and increased soil freezing on C and N cycling in northeastern forests. I conducted a laboratory experiment to study the effects of soil freezing on C and N losses during snowmelt. Organic horizon soils collected from mixed Acer saccharum-Fagus grandifolia and Picea rubens-Abies balsamea forests were incubated in severe, mild, and no soil frost conditions prior to snowmelt. Results show that losses of N in leachate, as well as total C and N fluxes (gases + leachate), were reduced following severe soil frost, indicating the response to winter climate depends on both the presence and severity of soil frost. I also implemented a snow removal experiment in a mixed Quercus rubra-Acer rubrum forest at Harvard Forest, MA to quantify the effects of depth and duration of snowpack and soil frost on CO2 losses from tree stems and soils. This study provides evidence that reduced snowpack and increased soil freezing may increase annual soil CO2 efflux, but have no significant effect on tree stem CO2 efflux. Taken together, results from my dissertation highlight the importance of winter climate as a driver of C and N fluxes in northeastern forests and suggest that while soil frost reduces C and N losses during snowmelt, annual losses of CO2 may increase Future studies investigating controls on C and N cycling in northeastern forests should account for changes in winter climate.

The alteration of the global environment by human activities is so widespread that scientists argue we've entered a new geologic epoch known as the Anthropocene. This dissertation examines the impact of human activities on biogeochemical cycling at the land-sea interface. I focus primarily on the role of land use/land cover (LULC) and coastal nutrient enrichment on silicon (Si) cycling in New England rivers and salt marshes. On land, Si is taken up by vegetation, improving plant fitness and protecting plants from a variety of environmental stressors. In aquatic systems, diatoms, the dominant type of phytoplankton in coastal temperate waters, require Si to survive. My research demonstrates that LULC is an important driver of Si export to coastal systems, accounting for 40-70% of the variability of riverine fluxes. Developed watersheds export significantly (p=0.03) more Si than their forested counterparts, which I hypothesize is due to less vegetated cover, a known Si sink, in developed watersheds. Building on this, I calculated the amount of Si fixed by land plants globally (84 Tmol yr-1) and the percent (55%) of global terrestrial net primary production that can be attributed to active Si-accumulating organisms. Next, I created the first complete salt marsh Si budget by quantifying tidal creek fluxes and net Si accumulation in a relatively undisturbed low-nutrient salt marsh. Further, comparing this Si accumulation to that of a high-nutrient marsh revealed that the high-nutrient marsh contained significantly (p<0.05) more Si within the sediments, roots, and porewater. Combining my original data from six New England salt marshes with published values, I quantify the mode of Si accumulation (rejective, passive, or active) by Spartina grasses and the environmental controls on such accumulation. Finally, using radionuclide tracers 137Cs and 210Pb, I calculated vertical accretion rates of five salt marshes and compared these values to historical measurements. I found that accretion rates have slowed and this deceleration is driven, in part, by a decrease in organic matter accumulation. Together, this dissertation improves our knowledge of Si cycling in terrestrial and aquatic ecosystems, and identifies previously unrecognized ways in which humans are perturbing biogeochemical cycles at the land-sea interface.

abstract: Biological soil crusts (BSCs) are critical components of arid and semiarid environments and provide the primary sources of bioavailable macronutrients and increase micronutrient availability to their surrounding ecosystems. BSCs are composed of a variety of microorganisms that perform a wide range of physiological processes requiring a multitude of bioessential micronutrients, such as iron, copper, and molybdenum. This work investigated the effects of BSC activity on soil solution concentrations of bioessential elements and examined the microbial production of organic chelators, called siderophores. I found that aluminum, vanadium, copper, zinc, and molybdenum were solubilized in the action of crusts, while nickel, zinc, arsenic, and zirconium were immobilized by crust activity. Potassium and manganese displayed behavior consistent with biological removal and mobilization, whereas phosphorus and iron solubility were dominated by abiotic processes. The addition of bioavailable nitrogen altered the effects of BSCs on soil element mobilization. In addition, I found that the biogeochemical activites of BSCs were limited by molybdenum, a fact that likely contributes to co-limitation by nitrogen. I confirmed the presence of siderophore producing microbes in BSCs. Siderophores are low-molecular weight organic compounds that are released by bacteria to increase element solubility and facilitate element uptake; siderophore production is likely the mechanism by which BSCs affect the patterns I observed in soil solution element concentrations. Siderophore producers were distributed across a range of bacterial groups and ecological niches within crusts, suggesting that siderophore production influences the availability of a variety of elements for use in many physiological processes. Four putative siderophore compounds were identified using electrospray ionization mass spectrometry; further attempts to characterize the compounds confirmed two true siderophores. Taken together, the results of my work provide information about micronutrient cycling within crusts that can be applied to BSC conservation and management. Fertilization with certain elements, particularly molybdenum, may prove to be a useful technique to promote BSC growth and development which would help prevent arid land degradation. Furthermore, understanding the effects of BSCs on soil element mobility could be used to develop useful biomarkers for the study of the existence and distribution of crust-like communities on ancient Earth, and perhaps other places, like Mars. / Dissertation/Thesis / Ph.D. Geological Sciences 2012

abstract: Despite public demand for climate change mitigation and natural open space conservancy, existing political and design efforts are only beginning to address the declining efficacy of the biotic carbon pool (C-pool) to sequester carbon. Advances in understanding of biogeochemical processes have provided methods for estimating carbon embodied in natural open spaces and enhancing carbon sequestration efficacy. In this study, the benefits of carbon embodied in dryland open spaces are determined by estimating carbon flux and analyzing ecological, social, and economic benefits provided by sequestered carbon. Understanding the ecological processes and derived benefits of carbon exchange in dryland open spaces will provide insight into enhancing carbon sequestration efficacy. Open space carbon is estimated by calculating the amount of carbon sequestration (estimated in Mg C / ha / y) in dryland open space C-pools. Carbon sequestration in dryland open spaces can be summarized in five open space typologies: hydric, mesic, aridic, biomass for energy agriculture, and traditional agriculture. Hydric (wetland) systems receive a significant amount of moisture; mesic (riparian) systems receive a moderate amount of moisture; and aridic (dry) systems receive low amounts of moisture. Biomass for energy production (perennial biomass) and traditional agriculture (annual / traditional biomass) can be more effective carbon sinks if managed appropriately. Impacts of design interventions to the carbon capacity of dryland open space systems are calculated by estimating carbon exchange in existing open space (base case) compared to projections of carbon sequestered in a modified system (prototype design). A demonstration project at the Lower San Pedro River Watershed highlights the potential for enhancing carbon sequestration. The site-scale demonstration project takes into account a number of limiting factors and opportunities including: availability of water and ability to manipulate its course, existing and potential vegetation, soil types and use of carbon additives, and land-use (particularly agriculture). Specific design challenges to overcome included: restoring perennial water to the Lower San Pedro River, reestablishing hydric and mesic systems, linking fragmented vegetation, and establishing agricultural systems that provide economic opportunities and act as carbon sinks. The prototype design showed enhancing carbon sequestration efficacy by 128-133% is possible with conservative design interventions. / Dissertation/Thesis / M.S. Landscape Architecture 2012

PERLATTI, Fábio. Trace metals biogeochemistry in soils and plants affected by mining waste rocks: consequences to ecosystem and options for restoration (Phytoremediation abd technosols). 2015.165 f. Tese (Doutorado em Ecologia e Recursos Naturais)-Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by Vitor Campos (vitband@gmail.com) on 2016-09-26T23:43:14Z No. of bitstreams: 1 2015_tese_fperlatti.pdf: 7190341 bytes, checksum: 1384a873edd02a706a01eb41b55a723f (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-09-26T23:46:34Z (GMT) No. of bitstreams: 1 2015_tese_fperlatti.pdf: 7190341 bytes, checksum: 1384a873edd02a706a01eb41b55a723f (MD5) / Made available in DSpace on 2016-09-26T23:46:34Z (GMT). No. of bitstreams: 1 2015_tese_fperlatti.pdf: 7190341 bytes, checksum: 1384a873edd02a706a01eb41b55a723f (MD5) Previous issue date: 2015 / The extraction and processing of metallic minerals generate large amounts of waste which, if not disposed of properly, may be sources of contamination and acid mine drainage; by contact of sulphides with water and oxygen; causing a decrease in pH and an increase in the mobility of metals in the soil. The diagnosis of biogeochemical behaviour of wastes can provide valuable information to discard and control the adverse effects of this kind of material, as well to support the adoption of more efficient measures of control and mitigation. This study had as general objective diagnose the impacts of waste disposal in an abandoned copper mine (Cu), as well to propose alternatives to mitigate the impacts and restore the environmental quality of the site, based on the hypothesis that such wastes can contaminate the soil with trace elements contained in minerals, and generate acid mine drainage, given the presence of sulphides exposed to weather conditions, hindering the natural regeneration of the ecosystem. The Chapter 1 provides an introduction to the theme, as well as a literature review. Chapter 2 presents a general diagnosis from the area, assessing the levels of several trace elements in rock wastes, soils and native plant species. In chapter 3, a thorough study on the geochemical behaviour of wastes, with focus on the generation of acid drainage were done, plus a detailed study about Cu behaviour in soils, through a chemical sequential extraction. Chapter 4 details the content of metals in above-ground tissues from plants that naturally grow on the wastes, assess the ability of these plants to be used in phytoremediation and show data about the changes that occur in the rhizosphere. Chapter 5 provides through a comparative study by sequential extraction in the rhizosphere and bulk soils; details about the changes that occur in the rhizosphere of plants and their consequences for Cu mobility and ecotoxicity, and finally, the chapter 6 presents an experimental study with the use of technosols, as way to immobilize the excess of labile copper in soil solution. Based on the results, can be concluded that the major impact is caused by the excess of Cu which still persists in the waste rocks and, through oxidation and dissolution processes, translocate large amount of metal into soil. The acid mine drainage was discarded given the buffering action generated by dissolution of carbonates, minimizing the negative effects of the oxidation of sulphides. The sequential extraction showed that the Cu concentration in soil is associated mainly with carbonates and amorphous iron oxides. The geochemical cycle between the dissolution of carbonates and oxidation of sulphides appears to be the main control mechanism of release and adsorption of Cu in soil. Regarding the plants, was concluded that they cannot be considered as Cu hyperaccumulators, however, high levels of metal were observed in roots, indicating that the survival strategy of these plants consists in immobilize metal in roots/rhizosphere. The sequential extraction in the rhizosphere showed that the presence of plants alter various soil characteristics under its influence, and also the geochemical behaviour of Cu. The technosols showed great ability to immobilize Cu. The four technosols elaborated in this study can immobilize more than 85% of Cu in solution, with the largest portion retained in the residual fraction, where Cu is adsorbed strongly, demonstrating that technosols emerge as an excellent alternative to remediate soils contaminated by metals. / A extração e beneficiamento de minerais metálicos geram grandes quantidades de rejeitos que se não dispostos adequadamente, podem ser fontes de contaminação e drenagem ácida; pelo contato de sulfetos com água e oxigênio; ocasionando diminuição no pH e aumento na mobilidade dos metais no solo. O diagnóstico do comportamento biogeoquímico de rejeitos pode fornecer informações valiosas para que se possa dispor e controlar adequadamente os efeitos adversos causados por esse tipo de material, bem como subsidiar a adoção de medidas de controle e mitigação mais eficientes. Esse estudo teve como objetivo geral, diagnosticar os impactos causados pela disposição de rejeitos em uma mina de cobre (Cu) abandonada, bem como propor alternativas para mitigar os impactos e restaurar a qualidade ambiental do local, baseado na hipótese de que esses rejeitos podem contaminar o solo da região com os elementos traço presentes nos minerais, além de gerar drenagem ácida, dada a presença de sulfetos expostos às condições atmosféricas, impedindo a regeneração natural do ecossistema. O capítulo 1 traz uma introdução ao tema, bem como uma revisão bibliográfica sobre o assunto. O capítulo 2 faz um diagnóstico geral da área, avaliando-se os teores de diversos elementos traço nos rejeitos, solos e plantas. No capítulo 3 foram aprofundados os estudos sobre o comportamento geoquímico dos rejeitos com foco na geração de drenagem ácida, além de um estudo detalhado do comportamento do Cu no solo, através da extração sequencial. O capítulo 4 detalha os teores de metais nos tecidos vegetais das plantas, avalia a aptidão do uso dessas espécies para a fitoremediação, bem como apresenta dados das alterações que ocorrem na rizosfera. O capítulo 5 aprofunda-se nas alterações que ocorrem na rizosfera das plantas e as consequências na mobilidade e ecotoxicidade do Cu, via extração sequencial, e por fim, o capítulo 6 apresenta um estudo experimental com a utilização de tecnosolos, para imobilizar o excesso de Cu lábil no solo. Os resultados indicam que o principal impacto é causado pelo excesso de Cu que ainda persiste nos rejeitos e que, por processos de oxidação e dissolução, translocam grandes quantidade do metal para o solo. A geração de drenagem ácida foi descartada; dada a ação tamponante gerada pela dissolução dos carbonatos, minimizando os efeitos negativos da oxidação dos sulfetos. A extração sequencial mostrou que o Cu no solo está associado principalmente aos carbonatos e óxidos de Fe amorfos. O ciclo geoquímico entre a dissolução dos carbonatos e oxidação dos sulfetos parece ser o principal mecanismo de liberação e adsorção do Cu no solo. Já as plantas estudadas, não foram consideradas hiperacumuladoras, entretanto, foram observados elevados teores de metal em suas raízes, indicando que a estratégia de sobrevivência dessas plantas consiste na imobilização do metal nas raízes/rizosfera. A extração sequencial na rizosfera mostrou que a presença das plantas altera as características do solo sob sua influência, e consequentemente o comportamento biogeoquímico do Cu. Já os tecnosolos demostraram grande capacidade em imobilizar Cu. Os quatro tecnosolos elaborados imobilizaram mais de 85% do Cu, sendo a maior parte retida na fração residual, que representa a fração onde o cobre fica adsorvido mais fortemente, demostrando que os tecnosolos despontam como uma excelente alternativa na remediação de solos contaminados por metais.